1. Field of the invention:
The present invention relates to a test device for evaluating microbial contamination of a liquid, in particular but not exclusively bacterial contamination of water supplied through a tubing system such as the water lines of a dental unit.
2. Brief description of the prior art:
Many microbial contamination test devices have been proposed in the prior art. Examples are given in the following United States patents:
______________________________________ 4,263,405 (Melnick et al.) 1981 4,639,419 (Olson et al.) 1987 5,081,017 (Longoria) 1992 ______________________________________
In many instances, microbial testing requires growth of the microorganisms of the liquid under test before adding the contamination indicating agent which colors the liquid in the presence of microorganisms. The above prior art test devices are not well suited for carrying out these two steps sequentially.